The two digital signal types are the on-off signal and the pulse train signal.

这两类数字信号分别为通断信号和脉冲序列信号。

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The remote control module controls the opening of valve by simulant signal. It also controls the open and the close of the valve by on-off signal.

远程控制模块实现远程模拟量对阀门开度大小的控制及远程开关量对阀门全开、全关的控制。

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Without conscious intent and the synchronizing signal of short iterations it is hard to notice the difference between being on the path and off the path unless you stay on the path for a while.

如果不是有意识地打算这样做，也没有短期迭代的同步信号，那么除非你在这条路上呆了很久，否则就很难注意到是否走错了路。

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Cars faced off on a two-lane, aluminum track, with a little red light blinking to signal who won.

WSJ: Gentlemen, Start Your Little Cars: These Derbies Are for Grown-Ups

According to Kenya's Daily Nation newspaper, the Consumer Federation of Kenya (Cofek) said the first notice about the analogue signal switch-off, planned for 31 December 2012, was given on 7 December 2012.

BBC: Kenyan digital TV switchover: Post-election date urged